Quantitative resistance to barley leaf stripe (Pyrenophora graminea) is dominated by one major locus

Pecchioni, Nicola; Faccioli, Primetta; Toubia-Rahme, H.; Valè, Giampiero; Terzi, Valeria

doi:10.1007/bf00225733

Cited by 56 publications

(30 citation statements)

References 20 publications

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“…This suggests that resistance cultivars have a better-adapted metabolism. The cross-breeding is found to split up these partial resistances (Knudsen, 1986;Pecchioni et al, 1996). Cross-breeding with a wide range of modern varieties accompanied with selection under natural infection conditions will lead to an accumulation of partial resistances again.…”

Section: Discussionmentioning

confidence: 99%

“…Under field conditions, the fungal pathotype (isolate) and the time of infection also were reported to have a role on the degree of escape (Skou and Haahr, 1987). For these reasons, the assessment of leaf stripe resistance by scoring disease incidence in a population of plants is more accurate than scoring disease severity on individual plants (Pecchioni et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

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Yield Responses of Barley to Leaf Stripe (Pyrenophora graminea) under Experimental Conditions in Southern Syria

Arabi¹,

Jawhar²,

Al-Safadi³

et al. 2004

Journal of Phytopathology

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The seed-borne pathogen, Pyrenophora graminea is the causal agent of barley leaf stripe disease. Field trials were undertaken to investigate the impact of leaf stripe on barley yield in two growing seasons in Southern Syria, by comparing plots with and without artificial inoculation. Ten barley cultivars originating from widely dispersed areas were used. The overall response to leaf stripe differed with the differences in susceptibility levels of the cultivars. Grain yield, the number of tillers, kernel weight and plant biomass decreased as disease severity increased. Diseased plants had fewer tillers, and as a consequence a reduced grain yield per plant. High yield losses resulted from leaf stripe in susceptible cultivars in Arrivate, Furat 1, WI2291 and Arabi Abiad with 44%, 50%, 73% and 92%, respectively. The cultivar Banteng had the best level of resistance to the disease, and is a candidate donor for resistance in future breeding programmes. As leaf stripe can dramatically reduce barley yields under favourable conditions, the disease should be considered by crop improvement programmes in Mediterranean and similar environments.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Yield Responses of Barley to Leaf Stripe (Pyrenophora graminea) under Experimental Conditions in Southern Syria

Arabi¹,

Jawhar²,

Al-Safadi³

et al. 2004

Journal of Phytopathology

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“…The P. graminea isolates were grown on PDA (Liofilchem, Italy), in Petri dishes at 20°C for 10 days in the dark. Seeds were surface-sterilized in 70% ethanol for 30 s and then in 5% sodium hypochlorite for 15 min prior to inoculation using the ‘sandwich’ technique [63].…”

Section: Methodsmentioning

confidence: 99%

The CC-NB-LRR-Type Rdg2a Resistance Gene Confers Immunity to the Seed-Borne Barley Leaf Stripe Pathogen in the Absence of Hypersensitive Cell Death

Bulgarelli

Biselli²,

Collins

et al. 2010

PLoS ONE

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BackgroundLeaf stripe disease on barley (Hordeum vulgare) is caused by the seed-transmitted hemi-biotrophic fungus Pyrenophora graminea. Race-specific resistance to leaf stripe is controlled by two known Rdg (Resistance to Drechslera graminea) genes: the H. spontaneum-derived Rdg1a and Rdg2a, identified in H. vulgare. The aim of the present work was to isolate the Rdg2a leaf stripe resistance gene, to characterize the Rdg2a locus organization and evolution and to elucidate the histological bases of Rdg2a-based leaf stripe resistance.Principal FindingsWe describe here the positional cloning and functional characterization of the leaf stripe resistance gene Rdg2a. At the Rdg2a locus, three sequence-related coiled-coil, nucleotide-binding site, and leucine-rich repeat (CC-NB-LRR) encoding genes were identified. Sequence comparisons suggested that paralogs of this resistance locus evolved through recent gene duplication, and were subjected to frequent sequence exchange. Transformation of the leaf stripe susceptible cv. Golden Promise with two Rdg2a-candidates under the control of their native 5′ regulatory sequences identified a member of the CC-NB-LRR gene family that conferred resistance against the Dg2 leaf stripe isolate, against which the Rdg2a-gene is effective. Histological analysis demonstrated that Rdg2a-mediated leaf stripe resistance involves autofluorescing cells and prevents pathogen colonization in the embryos without any detectable hypersensitive cell death response, supporting a cell wall reinforcement-based resistance mechanism.ConclusionsThis work reports about the cloning of a resistance gene effective against a seed borne disease. We observed that Rdg2a was subjected to diversifying selection which is consistent with a model in which the R gene co-evolves with a pathogen effector(s) gene. We propose that inducible responses giving rise to physical and chemical barriers to infection in the cell walls and intercellular spaces of the barley embryo tissues represent mechanisms by which the CC-NB-LRR-encoding Rdg2a gene mediates resistance to leaf stripe in the absence of hypersensitive cell death.

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“…Nematodes Fungi Insect Virus Bacteria Schiff et al (2000); Wilson et al (2000) Barley (Hordeum vulgare) Backes et al (1995Backes et al ( , 1996; Chen et al (1994); Heun (1992); Pecchioni et al (1996); Qi et al (1998); Steffenson et al (1996)…”

Section: Appendix Imentioning

confidence: 99%

The genetic architecture of disease resistance in plants and the maintenance of recombination by parasites

Kover

Caicedo

2001

Molecular Ecology

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Parasites represent strong selection on host populations because they are ubiquitous and can drastically reduce host fitness. It has been hypothesized that parasite selection could explain the widespread occurrence of recombination because it is a coevolving force that favours new genetic combinations in the host. A review of deterministic models for the maintenance of recombination reveals that for recombination to be favoured, multiple genes that interact with each other must be under selection. To evaluate whether parasite selection can explain the maintenance of recombination, we review 85 studies that investigated the genetic architecture of plant disease resistance and discuss whether they conform to the requirements that emerge from theoretical models. General characteristics of disease resistance in plants and problems in evaluating resistance experimentally are also discussed. We found strong evidence that disease resistance in plants is determined by multiple loci. Furthermore, in most cases where loci were tested for interactions, epistasis between loci that affect resistance was found. However, we found weak support for the idea that specific allelic combinations determine resistance to different host genotypes and there was little data on whether epistasis between resistance genes is negative or positive. Thus, the current data indicate that it is possible that parasite selection can favour recombination, but more studies in natural populations that specifically address the nature of the interactions between resistance genes are necessary. The data summarized here suggest that disease resistance is a complex trait and that environmental effects and fitness trade-offs should be considered in future models of the coevolutionary dynamics of host and parasites.

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Quantitative resistance to barley leaf stripe (Pyrenophora graminea) is dominated by one major locus

Cited by 56 publications

References 20 publications

Yield Responses of Barley to Leaf Stripe (Pyrenophora graminea) under Experimental Conditions in Southern Syria

Yield Responses of Barley to Leaf Stripe (Pyrenophora graminea) under Experimental Conditions in Southern Syria

The CC-NB-LRR-Type Rdg2a Resistance Gene Confers Immunity to the Seed-Borne Barley Leaf Stripe Pathogen in the Absence of Hypersensitive Cell Death

The genetic architecture of disease resistance in plants and the maintenance of recombination by parasites

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